Bicycles of semi-recumbent configuration have potential for greater comfort and speed than conventional bicycles that are ridden with upright posture. However, due to their configuration, semi-recumbent bicycles are more awkward to ride and significant practice is required of experienced riders of conventional bicycles to transition to them. For example, many of the long and short wheel base semi-recumbent bicycles have handlebars for steering mounted on a pivot point beneath the rider. Other semi-recumbent bicycles--mostly those with long wheel bases--have handle bars extending rearwardly from steering shafts mounted in a steering head positioned well forward of the rider. The result of this configuration is that the rider's hands sweep through a large radius arch, in the manner of a tiller on a boat, when steering rather than rotating about a near central pivot point as is typical of a conventional bicycle.
Semi-recumbent, four-wheel cycles are, on the other hand, stable and easy to ride. However, known primarily as utilitarian vehicles, they have been relegated to use in industrial applications for transportation of materials and people in novelty rental fleets near destination resorts and vacation areas. For many reasons they are not satisfactory for bicycle enthusiasts who ride for exercise and sport. For example, a typical four-wheel cycle has a frame constructed of jig-welded heavy steel tubing in a ladder frame configuration. Thus, it is comparatively very heavy and not considered portable by bicycle standards. Due to its weight and size, it cannot be easily carried atop an automobile like a bicycle in a roof top carrier. Outfitted with a canopy for sun or rain protection, relatively small wheels (e.g. 20" or smaller in diameter) and high gearing, the typical four-wheel cycle is intended to move only at modest speeds.
Furthermore, a typical four wheel cycle has one or both rear wheels driven using a chain drive system with sprockets that requires a long chain run length from the pedaling cranks to the rear wheels. Its ladder frame configuration usually has a fixed seat or an adjustable seat that moves along the ladder frame to accommodate riders of varying leg length. However, it does not compensate for torso length for steering purposes, thus placing the steering wheel or bars in an awkward position for many people.
Additionally, the typical four-wheel cycle does not have a suspension between the frame and wheels to dampen road shock to the rider and allow the tires to maintain constant contact with the road surface for traction and steering control. Instead it relies only on padding in the seat assembly and relatively thick pneumatic tires to dampen shocks to the rider. Without suspension, the framing and wheel sets must be built heavier and stronger to endure the shocks. Since it is not possible to stand up off the seat, as with a conventional bicycle, it can be very uncomfortable to control at high speeds on standard roadways and on off-road terrain. And, the heavy framing and thick pneumatic tires slow the cycle.